I think Onyx are the darker variant of a Perc but I'm no expert either. I really wanted an Onyx and the 2 Onyx breeder that I know of, Rod and Robin, doesn't have any for a while so I figure this was the closest thing to theirs. It's the first time I seen a True Perc this dark. It's actually darker than the picture but I think they are not happy being in the bag since they been in there for over 4 hours now. I got them in a cooler so hope they make it for another hour when I go home.